A typical solid state light engine includes one or more solid state light sources (such as but not limited to light emitting diodes (LEDs), organic light emitting diodes (OLEDs), polymer light emitting diodes (PLEDs), and/or any other semiconductor device that emits light (whether in the visible spectrum or not), and/or combinations thereof, whether connected in series, parallel, and/or combinations thereof, whether formed of one or more individual semiconductor dies, one or more chips, one or more packages, and/or combinations thereof.) driven by a driver circuit. Some driver circuits output a constant current drive signal. The solid state light sources may be configured in any number of ways, such as but not limited to parallel strings of series-connected solid state light sources. The driver circuit then generates an output voltage Vout across each of the parallel strings. The value of the output voltage may depend on the current level and the number of solid state light sources in each string.
Any individual solid state light source may fail at some point and that failure may result in an open circuit condition or a short circuit condition at that location in the circuit. Such failures may cause excess current to be diverted to the other solid state light sources and/or cause voltage surges in the light engine, which may in turn shorten the life of the remaining solid state light sources and/or the entire light engine, or result in premature failure of the light engine or damage to the driver circuit.